The well-known Géllé's test for the diagnosis of otosclerosis has been interpreted from a new point of view, and developed the new test method that is more sensitive and simple than previous one.The apparatus consists of audiometer, manometer and Politzer's balloon.The procedure of the test is as follows:The bone conduction sound of 250_??_4000cps, 40db above threshold is imparted to the ear tobe tested, then the pressure of external auditory canal is changed periodically by pressing Politzer's balloon twice a second.The pressure is gradually enhanced and the pressure when the bone conducting tone starts to pulsate is measured by the manometer.The results obtained with various deafness were as follows:1)The pressure was below 5 mmHg with those of normal hearing and perceptive deafness2)The pressure was above 60 mmHg in otosclerosis.3)In the case of other conductive deafness the pressure was.10_??_60 mmHg regardless to the presence of drum perforation.The pulsation of the bone conducting tone in this method has been proved by the experiments on the living human ear to be due to the distortion of the inner ear.This new method which mechanism is fundamentally different from the usual modified Géllé's test, has been designated by the author as″dynamic Géllé's test″.The original Géllé's test must be a kind of this dynamic method.